Interventions designed to reduce adolescent health risks often target parenting and family functioning. However, an ecological approach would suggest that interventions aimed at improving family functioning that exclusively target the family may be less efficient than interventions that target the contexts that give rise to family dysfunction. In keeping with this perspective, and in light of growing evidence that neighborhood residence has significant implications for family dynamics and adolescent health, the proposed study will examine adolescent health risk behaviors and their familial antecedents in the context of neighborhoods. Using data from the Project on Human Development in Chicago Neighborhoods (PHDCN) - an innovative study designed specifically to study adolescent development in the context of urban neighborhoods - we will address the following research questions using multilevel modeling: (1) Does neighborhood disorganization (e.g., poverty, crime, social disorder) predict adolescent health risk behaviors (substance use, delinquency, risky sexual behavior)? Does family dysfunction (ineffective parenting, family conflict, parent depression, parent health risk behaviors) explain associations between neighborhood disorganization and adolescent health risk behaviors? (2) Do contextual supports (peer social support and institutional resources) provide a buffer against the adverse effects of neighborhood disorganization on family functioning? (3) Do contextual supports (neighborhood collective efficacy, extra-familial social support, institutional resources) provide a buffer against the adverse effects of family dysfunction on adolescent health risk behaviors? In sum, the proposed study will examine three contextual domains that could potentially be targeted in future interventions: neighborhood disorganization, parents'support systems, and adolescents'support systems. The sample is a socioeconomically and racially/ethnically diverse group of adolescents from Chicago (n = 2,344). Adolescents, who were aged 9, 12 or 15 at baseline, and their parents were interviewed 3 times over 6 years. Neighborhood-level information comes from a separate survey of residents, as well as observational ratings made by trained data collectors.